1. Field of the Invention
The field of the present application pertains to medical devices. More particularly, the field of the invention pertains to a method for using lithotripsy to treat eye conditions or paranasal sinus conditions.
2. Description of the Background Art
A cataract is a clouding of the lens in the eye that affects vision. Most cataracts are related to aging. Cataracts are very common in older people. By age 80, more than half of all Americans either have a cataract or have had cataract surgery.
The lens lies behind the iris and the pupil. It works much like a camera lens. It focuses light onto the retina at the back of the eye, where an image is recorded. The lens also adjusts the eye's focus, letting us see things clearly both up close and far away. The lens is made of mostly water and protein. The protein is arranged in a precise way that keeps the lens clear and lets light pass through it. But as we age, some of the protein may clump together and start to cloud a small area of the lens. This is a cataract. Over time, the cataract may grow larger and cloud more of the lens, making it harder to see.
Age-related cataracts can affect vision in two ways. First, clumps of protein reduce the sharpness of the image reaching the retina. The lens consists mostly of water and protein. When the protein clumps up, it clouds the lens and reduces the light that reaches the retina. The clouding may become severe enough to cause blurred vision. Most age-related cataracts develop from protein clumping. Second, the clear lens slowly changes to a yellowish/brownish color, adding a brownish tint to vision. As the clear lens slowly colors with age, it may gradually cause vision to have a brownish shade. At first, the amount of tinting may be small and may not cause a vision problem. Over time, increased tinting may make it more difficult to read and perform other routine activities.
Surgery is the only real treatment for cataracts. Each year, cataract surgeons in the United States perform over three million cataract surgeries. One of the more conventional cataract surgery procedures is called extracapsular cataract extraction (ECCE). Extracapsular cataract extraction involves the removal of almost the entire natural lens while the elastic lens capsule (posterior capsule) is left intact to allow implantation of an intraocular lens. It involves manual expression of the lens through a large (usually 10-12 mm) incision made in the cornea or sclera. Although it requires a larger incision and the use of stitches, the conventional method may be indicated for patients with very hard cataracts or other situations in which phacoemulsification is problematic.
Modern cataract surgery is usually performed using a microsurgical technique called phacoemulsfication, whereby the cataract is emulsified with an ultrasonic handpiece and then suctioned out of the eye. Before phacoemulsification can be performed, one or more incisions are made in the eye to allow the introduction of surgical instruments. The surgeon then removes the anterior face of the capsule that contains the lens inside the eye. A phacoemulsification probe is an ultrasonic handpiece with a titanium or steel needle. The tip of the needle vibrates at ultrasonic frequency to sculpt and emulsify the cataract while a pump aspirates particles through the tip. In some techniques, a second fine steel instrument called a chopper is used from a side port to help with chopping the nucleus into smaller pieces. The cataract is usually broken into two or four pieces and each piece is emulsified and aspirated out with suction. The nucleus emulsification makes it easier to aspirate the particles. After removing all hard central lens nucleus with phacoemulsification, the softer outer lens cortex is removed with suction only. As with other cataract extraction procedures, an intraocular lens implant (IOL), is placed into the remaining lens capsule.
One possible improvement to phacoemulsification is a cataract surgery performed with lasers. Femtosecond Laser cataract surgery is rapidly emerging as a potential technology that may allow for improved precision of incision formation and emulsification of the cataract.
Although phacoemulsification and laser-based cataract surgery work well for many patients, these technologies have several shortcomings. For example, phacoemulsification ultrasound probes must propagate ultrasound energy along the length of the probe, from a proximal transducer to a distal tip. This propagation may lead to transmission of ultrasound energy along the probe to tissues in and around the eye that do not benefit from the transmission. Ultrasound probes also tend to generate more heat than would be desirable for a procedure in the eye. Finally, it may be quite difficult to steer an ultrasound probe around corners or bends, due to the mechanical requirements of propagating the ultrasound wave along the entire instrument. In other words, the probe may have to be rigid or at least more rigid than would be desirable.
Lasers have similar drawbacks. They may generate unwanted heat in the eye and are often difficult to control, thus risking damage to important nearby tissues. They also are easily damaged when attempting to navigate tight corners, as fibers in a laser probe may easily break.
Therefore, it would be advantageous to have a method and device for treating cataracts, and potentially other eye ailments, that included many of the advantages of phacoemulsification and laser procedures without at least some of the drawbacks. Ideally, such a method and device would be relatively simple to manufacture and implement, and would work well for performing cataract surgery without harming surrounding eye tissue. Also ideally, the method and/or device would be applicable to one or more other eye conditions.
Many people worldwide are afflicted by chronic or acute intermittent sinusitis, and it can often be a debilitating disease that affects one's ability to exercise, breathe, fly on airplanes, and the like. Chronic or acute intermittent sinusitis sufferers often experience symptoms such as drainage of a thick, yellow or greenish discharge from the nose or down the back of the throat, nasal obstruction or congestion, causing difficulty breathing through your nose, pain, tenderness and swelling around the eyes, cheeks, nose or forehead, reduced sense of smell and taste, ear pain, aching in the upper jaw and teeth, cough, which may be worse at night, sore throat, bad breath (halitosis), fatigue or irritability and nausea. Several types of surgical procedures have been developed to treat chronic sinusitis, such as functional endoscopic sinus surgery (“FESS”) and balloon sinuplasty. FESS is very invasive, however, and requires a long and painful recovery process. Balloon sinuplasty is less invasive but is not effective in all patients.
Therefore, it would be beneficial to have a new method and device for treating chronic and/or acute intermittent sinusitis. Ideally, such a method and device would be minimally invasive and require minimal recovery time. At least some of these objectives, as well as at least some of the objectives discussed above, will be met by the embodiments described herein.